1. Technical Field
This disclosure generally relates to an electron-emitting device manufacturing apparatus using a surface conduction electron-emitting element, a solution used for the electron-emitting device manufacturing apparatus and an electron-emitting device manufactured by using the solution, and an image displaying apparatus using the electron-emitting device.
2. Description of the Related Art
Conventionally, two types of a thermoelectric source and cold cathode electronic source are known as an electron emitting device. A field emission type (hereinafter, called FE type), a metal/insulating layer/metal form (hereinafter, called MIM type), and a surface conduction electron-emitting element are known as the cold cathode electronic source. As example of the FE type, “W. P. Dyke & W. W. Dolan, “Field emission”, Advance in Electron Physics, 8 89 (1956)” (reference 12) and “C. A. Spindt, “Physical Properties of thin-film field emission cathodes with molybdenium” J. Appl. Phys., 475248 (1976)” (reference 13) are known. As an example of the MIM type, “C. A. Mead, “The Tunnel-emission amplifier”, J. Appl. Phys., 32 646 (1961)” (reference 14) is known.
As an example of the surface conduction electron-emitting element type, “M. I. Elinson, Radio Eng. Electron Phys., 1290 (1965)” (reference 15) is known. By applying a current to emulsion side in parallel on a thin film on a small area formed on a substrate, the surface conduction electron-emitting element causes electron emission. That phenomenon is utilized. As the surface conduction electron-emitting element, use of a SnO2 thin film is disclosed by Elinson, use of an Au thin film is disclosed in “G. Dittmer, “Thin Solid Films”, 9 317 (1972)” (reference 16), use of In2O3/SnO2 thin film is disclosed in “M. Hartwell and C. G. Fonstad, “IEEE Trans. ED Conf.”, 519 (1975)” (reference 17), and use of a carbon thin film is disclosed in “Hisashi Araki et all, “Vacuum”, vol. 26, no. 1, page 22, (1983)” (reference 18).
As a typical element configuration, an element configuration disclosed by M. Hartwell described above is shown in FIG. 1. In FIG. 1, the element configuration of M. Hartwell includes a substrate 1, electrodes 2 and 3, a conductive thin film 4, and an electron emitting part 5. The conductive thin film 4 is made from a metal oxide thin film formed by a spatter in a pattern of an H shape, and the electron emitting part 5 is formed by an electric process called an electric forming (described later). In FIG. 1, a length L1 between the electrodes 2 and 3 is defined to be from 0.5 mm to 1 mm, and a Width W1 is defined to be 0.1 mm.
In the conventional surface conduction electron-emitting element, the electron emitting part 6 is generally formed by conducting the electric process called the electric forming with respect to the conductive thin film 4 before the electron emission is conducted. In the electric forming, a DC voltage or enormously slow rising voltage, for example, approximate 1V/min is applied to both ends of the conductive thin film 4, and then the conductive thin film 4 is locally violated, transformed, or degenerated, so that the electron emitting part 5 is formed in a state being electrically a high resistance. At the electron emitting part 5, the conductive thin film 4 is partially cracked, and the electrons are emitted from that crack. The surface conduction electron-emitting element to which an electric forming process is conducted applies a voltage to the conductive thin film 4, and applies a current to the element, so that the electron emitting part 5 emits electrons.
Advantageously, since the above-described surface conduction electron-emitting element can be easily manufactured because of its simple configuration, a plurality of elements can be arranged and formed in a larger area. Applied researches have been conducted for a charged beam source a display unit, or a like by taking advantages of the above-described features. As an example in that a plurality of surface conduction electron-emitting elements are arranged and formed, as described later, the surface conduction electron-emitting elements are arranged in parallel called a quarter line arrangement, and both ends of each element are wired (called a consensus sequence) and a cross-lined row is arranged in multiple lines in the electronic source (for example, see references 1-3).
Moreover, in an image forming apparatus as the display unit or a like, recently, a tabular type display unit using a liquid crystal has been spread instead of a CRT (Cathode Ray Tube). However, there is a problem in that the tabular type display unit is required to have a backlight because the tabular type display is not a self-luminous type. Thus, it has been desired to develop the display unit of self-luminous type. As a self-luminous type display unit, an image forming apparatus is disclosed as the display unit combining the electronic source arranging the plurality of the surface conduction electron-emitting elements and a fluorescent material emitting a visible light by the electron emitted from the electronic source (for example, see the reference 4).
However, in the conventional surface conduction electron-emitting device manufacturing method, a photolithography etching method in a vacuum deposition and a semiconductor process is frequently used, and in order to form the elements in the larger area, a large number of steps and higher production cost are required to produce the electron-emitting device.
As for the above-described problems, in order to form the conductive thin film of a device part of the surface conduction electron-emitting element as described above, without depending on a vacuum deposition method and a photolithography etching method, the inventor considers to form the conductive thin film at a stable preferable yield ratio and a low cost by applying an ink-jet droplet providing means known as U.S. Pat. No. 3,060,429 (reference 5), Japanese Laid-open Patent Application No. 3298030 (reference 6), Japanese Laid-open Patent Application No. 3596275 (reference 7), Japanese Laid-open Patent Application No. 3416153 (reference 8), Japanese Laid-open Patent Application No. 3747120 (reference 9), and Japanese Laid-open Patent Application No. 5729257 (reference 10). Then, the inventor discloses a result of studying a practical producing method in a broad range in Japanese Laid-open Patent Application No. 2001-319567 (reference 11).
However, there are still various unsolved problems in order to stably jet and provide a solution including an element to be the conductive thin film on the substrate because of differences from a method for jetting an ink toward a paper sheet and a method for recording by an ink-jet. For example, since such this element is generally a metal element, there are still unknown parts in technologies of successively stably jetting for a long term. Especially, in order to make a jet performance stable for a long term, a clogging problem should be solved.
Conventionally, in a field of an ink-jet record using a record liquid in which a water soluble dye is dissolved, a nozzle of a head is generally from a range from Φ33 μm to Φ34 μm (approximate 900 μm2 in area) to a range from Φ50 μm to Φ51 μm (approximate 2000 μm2 in area), and a dye is dissolved in a liquid medium. Accordingly, the clogging problem is eliminated. However, even such conventional technology cannot solves the clogging problem in a condition of stably jetting the ink from a minute nozzle, for example, under Φ25 μm (smaller than 500 μm2 in area) which does not exist in the conventional technology, for a long term.